NetPrint-pres-04 (2)

8/7/2019 NetPrint-pres-04 (2)

1/31

NETWORK OF COMPETENCE IN FORMATION

OF SURFACE PROPERTIES

MOLPRINT MOLECULAR UNDERSTANDINGOF PRINTABILITY

Jarl B. Rosenholm, bo Akademi University (coordinator)Martti Toivakka, bo Akademi University

Kai-Erik Peiponen, University of Joensuu

Jussi Timonen, University of Jyvskyl (University of Oulu)

Matti Murtomaa, University of Turku

Heidi Fagerholm, Top Analytica, Turku


2/31

NETWORK OF COMPETENCE IN FORMATION

OF SURFACE PROPERTIES

MOLPRINT INDUSTRIAL PROJECTPARTNERS

M-real OyjStoraEnso Oyj

Omya Oy

Ciba Specialty (Raisio) Chemicals Oy

Hansaprint Oy

KSV Instruments Oy


3/31

MOLPRINTPaper grade

Printing speed

Uncoated fine

paper

Coated fine

paper

Photographic

paper

New

papers

Recycled paper

Newpapers

New printing tech-niques require arange of coated andnoncoated paper

qualities.

Advanced inks arepigment based,solvent based orwater based, which

should set fastwithout mottling


4/31

MOLPRINTWHYThe diverging requirements set by new printing techniques has

made the traditional specification standards used by paper

manufacturers (Bendtsen, PPS, Cobb, HST) unsatisfactory,

which is considered to be the greatest obstacle for a fastdevelopment of this industry.

HOW

Paper qualities aimed for different printing techniques are

characterised thoroughly with physico-chemical and structural

means in two- and three-dimensions, in order to establish new

common standards for the printers and for the paper makers.


5/31

MOLPRINT

DigitalorInk

-Jetprintin

g

Offsetorflexoprinting

BASE PAPER / SC / COATED PAPER / PACKAGES

CALENDERING / SURFACE SIZING / COATING

CALENDERING / SURFACE SIZING / COATING

PRINTING METHOD A

PRINTING METHOD B

The research has to account for all the process stages


6/31

MOLPRINTWHAT will be done

Chemical and physical surface and bulk properties

Surface (2D) and cross-sectional (3D) structure

2D- and 3D- transport and setting of printing ink

Optical properties related to visual response

Heat transport and electric/hydrostatic conductivity


7/31

MOLPRINTManufactur ingUp-scaling

StructureSurfaceCross-section

Analyses

Structure PhysicalChemical

Techniques

PrintabilityA / Paper X (X)

A / Phys.Chem . X

Top Analytica X (X) X

JoU / Physics X

JyU / Phys ics + Ou lu * X (X )

TY / Physics X

* Oulu Univ./ Optoelectronics:Opt ica l Coherence Tom ography

In ktransportAdsorptio

Opticalproperties

Conductivity(heat &electric)WHO

is doing


8/31

MOLPRINTPigment Coated Papers

Laboratory of Paper Coating and Converting, bo Akademi University

To understand the interactions that occur in various printingprocesses between printing liquids (inks, emulsified inks, foun-tain solutions) and pigment coated papers

Through use of both experiments and mathematical modeling,the project strives to identify those chemical and morphologicalproperties of inks and coated paper surface that control theprintability and quality of coated paper products


9/31

MOLPRINTHOW it will be done

Influence of ink constituents and paper surface characteristicson the ink tack development, ink setting and ink adhesion areinvestigated

Ink constituents are separated chromatographically

The microstructure and chemistry in commercial inks isanalyzed and consequences for the printability and print qualityis evaluated

Properties ink/fountain solution emulsions are measured


10/31

MOLPRINTEXPERIMENTAL PROCEDURES

Hg-porosimetry

Thin-layer wicking (TLW)

Thin-layer chromatography (TLC, into latex)

Tack, gloss, print density etc.

Rotogravure Flexo Heat/coldset offset


11/31

MOLPRINTMODELING: Current models ignore chemistry!

Develop 2D surface and 3D bulk model of coatingstructure, including heterogeneity caused by chemistry

Clarify the influence of nonuniformities on dominantmechanisms that control printability and print quality


12/31

MOLPRINTInk and Solvent Interaction and their Transport during Printing

Department of Physical Chemistry, bo Akademi University

Relate the surface energy and structure with the dynamic 2D-spreading and setting of inks on pigment coated papers

Investigate the simultaneous fast 2D- and 3D-penetration ofmodel solutions into the bulk paper structure (ink-jet printing).

A mathematical model is developed:

which describes the liquid transport and ink setting processes

serves as a new specification for printers and paper makers


13/31


The surface energy and spreading is measured as wetting ( )The surface structure and interaction energy with AFM

The setting speed, e.g. with D-QCM

The penetration is investigated as 2D-3D-liquid flow

The amount ofliquid absorbed is evaluated from volumetric

and/or geometric considerationsThe binding of inkis characterized spectrometrically


14/31

MOLPRINT

HP-H 2O-0,18 l

0

20

40

60

80

100

120

0 50 100 150 200

tid[s]

mtn. 1

mtn. 2

mtn. 3

mtn. 4

mtn. 5

mtn. 6


15/31

MOLPRINT

cos

cos *

-1 0 1

0

1

-1


16/31

MOLPRINTInterfacial structures Process aspect

Top Analytica, Ltd

Characterize the physical surface and cross-sectional structureof paper and coating layers molecular structure

Identify the surface chemical structure of paper and coatinglayers macroscopic properties

The relationship between these properties how shouldprintability be defined

Identify the most suitable analytical techniques for studying ofthe above mentioned relationships


17/31


The paper manufacturing is investigated step-by-step, from thebase paper to the printed product as case studies, including:

Base paper structure Structure after calendering

Structure after surface sizing/coating Printabilty

In between these steps; surface properties, interaction betweenprocess chemicals and pigments and the interaction between theink and the surface is analyzed


18/31

MOLPRINTEXPERIMENTAL PROCEDURES

(SEM)-EDX ~ m

TOF-SIMS < 2 nm

280285290

Binding Energy (eV)

Na+

Mg +K

100 m

ESCA

2 - 5 nm


19/31

MOLPRINTEXPERIMENTAL PROCEDURESBlue = CaCO3Green = Kaolin

Red / Brown =

C, O

200 m


20/31

MOLPRINT

Optical measurement of print qualityDepartment of Physics, University of Joensuu

Unfortunately, the variation of gloss deteriorates the print quality.

The gloss depends on various paper and printing variables such as the

micro-roughness and texture of paper, absorption of ink and spectro-scopic properties of the ink.There are conventional glossmeters that give information on relativelylarge area and provide a number, which is related to the average gloss

of a surface.

Unfortunately, such devices are not sensitive to detect gloss in normaldirection which is the usual geometry for visual evaluation namely thatof reading news papers or magazines.


21/31

MOLPRINT

HOW is it done

The setup of DOG isThe setup of DOG isshown in figureshown in figure

We have developed a novel glossmeter thatis based on detection of local gloss variationby a diffractive element based glossmeter(DOG). It is free of the problems related tothe conventional glossmeters (see. KariMyller A glossmeter based on a diffractiveoptical element, University of Joensuu,Department of Physics, Dissertations 42(2004)). This device is sensitive to small gloss

variation of planar and curved surfaces.Furthermore, it can be utilized for detectionof average gloss from a macroscopicsurface.


22/31

MOLPRINT

HOW it will be done

The key point of the DOG is the diffractive optical element(DOE), which is a computer-generated hologram andfabricated using modern electron beam lithography. DOE is

exploited as an analyser of the amplitude and phase of thereflected light field from the print. It provides, e.g.:

Information on the quality of the print itself such as glossvariation.

Information on anisotropy of the surface morphology on

print area.Thus, it is an useful device for quality inspection of prints


23/31

MOLPRINT

Effect of nip pressure and calandering on the surfacemorphology and bulk structure of paper

Department of Physics, University of Jyvskyl

Understand morphological changes induced in the

structure of paper by nip pressure andcalandering.

To relate these morphological changes to printingquality


24/31

MOLPRINT

HOW it will be done

X-ray Microtomography (XMT)Department of Physics, University of Jyvskyl

resolution ~ 0.9 m

complete 3-D internal structure

Optical coherence tomography (OCT)Optoelectronics and Measurement Techniques Laboratory,

University of Oulu

resolution ~ 10 m

penetration depth ~ 40 m


25/31

MOLPRINT

Computer

microfocu

s X-ray

tube

object

manipulat

or

X-ray CCD

camerasample

3D image

X-ray Microtomography (XMT)

Uses X-rays toproduce 2Dshadowgrams

from multipleangles

Reconstructs3D imagesfrom shadow-grams

Nondestructive no sample preparation needed

Sample sizes from 2mm-68 mm with respective voxel sizes 0.9-20 m


26/31


27/31

MOLPRINTOptical coherence tomography (OCT), Optoelectronics andMeasurement Techniques Laboratory, University of Oulu


28/31

MOLPRINT

Heat transport and electrical conductionLaboratory of Industrial Physics, University of Turku

Electrostatics play an important role in, for example:

xerography, gravure printing, laser and ink jet printing further handling of printouts

future products & processes (intelligent papers and packages, ...)

Thermo-analytical properties:

heat conduction in paper and polymers

high printing speed > small melting time


29/31

MOLPRINT

HOW it will be done

Development of new electrostatic methods for studying:

electrical conduction and charge decay

charging properties of papers and polymers

effects of moisture, morphology, composition etc. on theelectrostatic properties

Development of new thermo-analytical methods

heat conduction in polymers and papers with differentcomposition & morphology


30/31

MOLPRINT

_1015153502_001.jpg

Effect of surface coverage of a glass pipe by small particles on thetriboelectrification of magnesium stearate doped glucose powder


31/31

MOLPRINT

Thank you for your attention!

Documents

NetPrint-pres-04 (2)